Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • School
  • The sum of first 26 terms of an A.P a1,a2,a3,...... If a2+a6+a9+a18+a21+a25=165 is

The sum of first 26 terms of an A.P a1,a2,a3,...... If a2+a6+a9+a18+a21+a25=165 is

Answers (1)

best_answer

Solution:  We have ,

                a_1+a_26=a_2+a_25=a_3+a_24=.......=a_9+a_18

        Thus ,

              a_2+a_6+a_9+a_18+a_21+a_25=165

             Rightarrow  (a_2+a_25)+(a_6+a_21)+(a_9+a_18)=165

           Rightarrow    3(a_1+a_26)=165  Rightarrow (a_1+a_26)=55

          herefore     a_1+a_2+a_3+..........+a_26=(26/2)(a_1+a_26)=13 imes 55=715.

Posted by

Deependra Verma

View full answer

Similar Questions

Latest Question